COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT Summary of Concentration of Credit Risk (Details) - Commercial loans held-for-investment - Commercial real estate portfolio segment	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	100.00%	100.00%
Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	100.00%	100.00%
Multifamily | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	94.00%	89.60%
Healthcare | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	5.50%	6.40%
Self-Storage | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	0.50%	1.80%
Retail | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	0.00%	1.60%
Office | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	0.00%	0.60%
South | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	43.50%	46.60%
Southwest | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	29.40%	26.70%
Mid-Atlantic | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	15.00%	12.40%
Midwest | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	7.90%	8.00%
West | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (as a percentage)	4.20%	6.30%